1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device which forms pixel electrodes and counter electrodes on a liquid crystal surface side of one substrate out of respective substrates which are arranged to face each other with liquid crystal therebetween.
2. Description of the Related Art
This type of liquid crystal display device is configured to control a quantity of light which passes through a region defined between pixel electrodes and counter electrodes by driving liquid crystal to which an electric field generated between respective electrodes is applied.
Such a liquid crystal display device has been known as a display device which exhibits excellent property in a so-called wide viewing angle, wherein the display is not changed even when viewed from the oblique direction with respect to a display surface.
Heretofore, the pixel electrodes and the counter electrodes are formed of a conductive layer which prevents light from passing through these electrodes.
However, recently, there has been known a liquid crystal display device having the constitution in which counter electrodes formed of a transparent electrode are formed over the whole area of a pixel region except for a periphery of the pixel region, and strip-like or comb-teeth-shaped pixel electrodes are arranged over the counter electrodes by way of an insulation film in a state that the transparent electrodes extend in one direction and are arranged in parallel in the direction which intersects one direction.
The liquid crystal display device having such a constitution generates an electric field which is substantially parallel to substrates between the pixel electrode and the counter electrode and hence, the liquid crystal display device can largely enhance a so-called numerical aperture while still ensuring the excellent wide viewing angle property.
Further, in such a constitution, when short-circuiting arises between the pixel electrode and the counter electrode which is arranged below the pixel electrode by way of an insulation film through a pin hole, a so-called point defect arises. As a liquid crystal display device which can overcome such a point defect, there has been known a liquid crystal display device disclosed in Japanese Patent Laid Open 2005-148534 which is a patent application filed prior to this application filed by the same applicant. Family of this application is co-pending in the U.S. application Ser. No. 10/977,934.
In this literature, there is disclosed the constitution in which two pixel electrodes which are physically separated from each other are formed on the pixel region, and a video signal is supplied to these respective pixel electrodes through two respective thin film transistors which are turned on simultaneously in response to a scanning signal from a gate signal line.
Such a liquid crystal display device obtains an advantageous effect that even when one pixel electrode is short-circuited with the counter electrode, another pixel electrode still performs a function thereof and hence, a point defect does not occur.